ElasticSearch Java Api(二) -检索索引库

上篇博客记录了如何用Java调用api把数据写入索引，这次记录下如何搜索。

一、准备数据

    String data1 = JsonUtil.model2Json(new Blog(1, "git简介", "2016-06-19", "SVN与Git最主要的区别...")); String data2 = JsonUtil.model2Json(new Blog(2, "Java中泛型的介绍与简单使用", "2016-06-19", "学习目标 掌握泛型的产生意义...")); String data3 = JsonUtil.model2Json(new Blog(3, "SQL基本操作", "2016-06-19", "基本操作：CRUD ...")); String data4 = JsonUtil.model2Json(new Blog(4, "Hibernate框架基础", "2016-06-19", "Hibernate框架基础...")); String data5 = JsonUtil.model2Json(new Blog(5, "Git基本知识git", "2016-06-19", "Shell是什么...")); String data6 = JsonUtil.model2Json(new Blog(6, "C++基本知识", "2016-06-19", "Shell是什么...")); String data7 = JsonUtil.model2Json(new Blog(7, "Mysql基本知识", "2016-06-19", "git是什么..."));

二、查询

一次查询可分为下面四个步骤：

• 1.创建连接ElasticSearch服务的client. 
  索引在ElasticSearch服务器上，进行索引的查询首先要和服务器创建连接，这是第一步。

  Client client = TransportClient.builder().build()
              .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300));
  

• 2.创建QueryBuilder. 
  QueryBuilder可以设置单个字段的查询,也可以设置多个字段的查询. 
  e.g.1: 查询title字段中包含hibernate关键字的文档:

  QueryBuilder qb1 = termQuery("title", "hibernate");
  

  e.g.2: 查询title字段或content字段中包含Git关键字的文档:

  QueryBuilder qb2= QueryBuilders.multiMatchQuery("git", "title","content");
  

• 3.执行查询 
  通过client设置查询的index、type、query.返回一个SearchResponse对象：

  SearchResponse response = client.prepareSearch("blog").setTypes("article").setQuery(qb2).execute()
              .actionGet();
  

• 4.处理查询结果 
  SearchResponse对象的getHits()方法获取查询结果,返回一个SearchHits的集合，遍历集合获取查询的文档信息：

  SearchHits hits = response.getHits();
  

三、java代码实现

package cn.com.bropen.es;

import java.net.InetAddress; import java.net.UnknownHostException; import org.elasticsearch.action.search.SearchResponse; import org.elasticsearch.client.Client; import org.elasticsearch.client.transport.TransportClient; import org.elasticsearch.common.transport.InetSocketTransportAddress; import org.elasticsearch.index.query.MultiMatchQueryBuilder; import org.elasticsearch.index.query.QueryBuilder; import org.elasticsearch.index.query.QueryBuilders; import org.elasticsearch.search.SearchHit; import org.elasticsearch.search.SearchHits; import static org.elasticsearch.index.query.QueryBuilders.*; public class ElasticSearchGet { public static void main(String[] args) { // client startup try { Client client = TransportClient.builder().build() .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300)); QueryBuilder qb1 = termQuery("title", "hibernate"); QueryBuilder qb2= QueryBuilders.multiMatchQuery("git", "title","content"); SearchResponse response = client.prepareSearch("blog").setTypes("article").setQuery(qb2).execute() .actionGet(); SearchHits hits = response.getHits(); if (hits.totalHits() > 0) { for (SearchHit hit : hits) { System.out.println("score:"+hit.getScore()+":\t"+hit.getSource());// .get("title") } } else { System.out.println("搜到0条结果"); } } catch (UnknownHostException e) { e.printStackTrace(); } } }

查询结果：

log4j:WARN No appenders could be found for logger (org.elasticsearch.plugins).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
score:0.5:  {posttime=2016-06-19, id=1, title=git简介, content=SVN与Git最主要的区别...} score:0.17673586: {posttime=2016-06-19, id=7, title=Mysql基本知识, content=git是什么...} score:0.049935166: {posttime=2016-06-19, id=5, title=Git基本知识git, content=Shell是什么...}

参考资料：

1. 分布式搜索elasticsearch java API 之（五）——搜索
2. GET API
3. elasticsearch中文指南–java-api
4. 高亮显示